The present disclosure relates to a transmission system and more particularly, to a baffle for meshing gears in a bearing compartment of a transmission system.
A gas turbine engine typically includes a transmission system for coupling one of its spools to an accessory gearbox. Such a transmission system includes a first bevel gear (often called the bull gear) mounted to a shaft of the spool. The transmission system also includes a tower shaft and an associated second bevel gear (often referred to as the bevel gear) mounted to a first end of the tower shaft, where a second end of the tower shaft is coupled to the accessory gearbox.
The transmission system also typically includes a baffle configured to cover at least a portion of the bevel gear. Such a baffle is provided so as to prevent surplus lubricant churning within the bearing compartment, in which the transmission system is located, from impinging on that portion of the bevel gear, since such surplus lubricant impingement typically increases windage and fluid drag on the bevel gear. However, such a baffle also captures and traps lubricant which is propelled off of the bevel gear, which causes power loss, efficiency reduction and heat generation as it churns, looking for an exit path from the baffle. This captured lubricant churns within the space between the bevel gear and the baffle and thereby causes windage and fluid drag on the bevel gear.
To prevent lubricant impingement, the baffle is installed around the first bevel gear. However, lubricant passing out of the baffle includes a large amount of energy that can be transferred to the gears and other rotating components within the compartment, which decreases the efficiency of the engine.